General Introduction - Integrated Assessment of Health and Sustainability of Agroecosystems - page 15

persons per square kilometer (Government of Kenya, 1994). Altitudes range from
1,400 m in the southeast to 2,400 m in the north. Rainfall is bimodal with the two
peaks in April/May and October/November. Average rainfall is 1,100 mm per year.
The most predominant soil type is nitisols (red Gikuyu loams). The combination
of good soils, suitable climate, well-developed infrastructure, and the proximity to
the country's main market (Nairobi) makes the district the most economic farming
region in the country. Vegetable cultivation and dairy production (zero grazing) are
the most feasible farming activities because of the small farm sizes and the high
demand for produce in the city. Coffee, tea, pyrethrum, maize, beans, and bananas
are also grown. Livestock are mainly dairy cattle of exotic breeds or their crosses
with indigenous breeds.
The average farm size is 1.1 ha per household of 4.8 people (Jaetzold and
Schmidt, 1983). Most of the land is devoted to crop production (Stotz, 1983), with
the remainder used as a dwelling place for humans and housing for cattle. Very few
smallholdings have pastures. Livestock are integrated with cropping activities under
which crop by-products are used as fodder, while manure is used as fertilizer. The
cattle are permanently housed (zero grazing) and hand-fed on fodder crops, crop
residues, grass, and other material collected off the farm and commercial feeds. In
most households, farming is a supplemental source of income since most households
rely on off-farm employment for their main income.
There is a great potential to increase output per farm and per unit area of land in
the mixed smallholder farms (Walshe et al., 1991). This can be achieved with the use
of improved technology and inputs (McIntire et al., 1992). Hudson (1989) suggested
that to increase yields, the primary requirement is not research into new methods,
but the increased application of techniques and practices that are already known.
Other requirements are improved crop varieties and livestock breeds, more research
into local conditions, more use of fertilizers, more capital, more mechanization, and
reduction of wastage from pest and disease.
1.6 PotentIal IndIcatoRs
From a national point of view, the goals of the Kiambu agroecosystem would include
the stability and productivity of rural livelihoods, supplying wholesome produce for
Nairobi, and producing cash crops (coffee and tea) for export. While these under-
lie the perceived efficacy and effectiveness of the Kiambu agroecosystem, other
health and sustainability attributes depend on internal, systemic perspectives of its
goals and objectives and how these relate to key biophysical and socioeconomic
factors of the agroecosystem. Any list of indicators that does not consider this is not
likely to be functional in the practical decision-making processes of the agroeco-
system. What are these goals, and what are the key biophysical and socioeconomic
factors? What attributes are more important in defining the health of the Kiambu
agroecosystem? An agroecosystem assessment must first seek to address these ques-
tions before setting out lists of things to measure. It follows that indicators are part
of the results of the process rather than the driver.
A distinguishing feature of Kenyan smallholder agriculture is the existence of
the village as an important level in the agricultural hierarchy. At this level, there is a